public virtual HttpRequest Create(HeadDocumentRequest request)
        {
            Ensure.That(request, "request").IsNotNull();

            return new HttpRequest(HttpMethod.Head, GenerateRelativeUrl(request))
                .SetRequestTypeHeader(request.GetType())
                .SetIfMatchHeader(request.Rev);
        }
        protected virtual string GenerateRelativeUrl(HeadDocumentRequest request)
        {
            var urlParams = new UrlParams();

            urlParams.AddIfNotNullOrWhiteSpace("rev", request.Rev);

            return string.Format("/{0}{1}", new UrlSegment(request.Id), new QueryString(urlParams));
        }